Integument II Flashcards
Dermis: Papillary layer
Superficial layer • Loose connective tissue (more cells) • Contains blood vessels • Predominately type I and III collagen fibers • The elastic fibers are threadlike and form an irregular network Contains Meissner corpuscles
Dermis: Reticular Layer
• Considerably thicker than and deep to the papillary layer • Dense irregular connective tissue (less cells) • Characterized by thick irregular bundles of mostly type I collagen and courser elastic fibers
Epidermal ridge, dermal ridge, dermal papillae
Areas of increased mechanical stress has deeper epidermal ridges and longer, more closely spaced dermal papillae Responsible for fingerprinting
Epidermal Appendages: Nails
Hard plates of epidermal keratinized cells
• Present on the dorsal surface of the distal phalanx of the fingers and toes
• Help with grip
• Gives protection
pithelial Appendages: Hair Follicle
• Cylindrical shafts composed of keratin • Produced in follicles • Associated with sebaceous gland -• Found in thin skin only -Consists of • Infundibulum • Isthmus • Inferior segment
Hair follicle and hair formation
Matrix cells contribute to
formation of the internal root
sheath and the hair shaft
Keratogenous zone:
matrix cells
undergo keratinization as soon as
they pass through this zon
fully keratinized hair
-consisting of hard keratin is not followed by the internal root sheath • It is separated from the underlying dermis via a thick basal laminal
Process of hair growth-Cyclical process
Occurs in three (3) phases:
• Long phase of active growth (anagen)
• Short phase of involution (catagen)
• Short inactive phase (telogen)
• Growth cycle varies from site to site:
Pubic hairs, coarse trunk hair, eyelashes, eyebrows have a short growth phase (anagen) and
a relatively long resting phase (telogen) hence they are not so long
Epidermal Appendages: Sebaceous glands
Simple branched acinar gland ▪ Secretory portion ▪ Located deeper dermis ▪ Opens into hair follicle ▪ Secretion is holocrine ▪ Product is sebum
Epidermal Appendages: Eccrine sweat glands
Found in thick and thin skin ▪ Simple coiled tubular glands ▪ Innervation: cholinergic ▪ Secretory portion is in the deep dermis, ▪ Undergoes merocrine mode of secretion
• Duct passes through the dermis and epidermis to
open onto the surface
-Eccrine sweat glands
-– Composed of stratified cuboidal epithelium
consisting of a basal layer and a luminal layer
Epidermal Appendages: Apocrine glands
- armpit and perineum ▪ Coiled tubular glands ▪ Secretory portion in the dermis or even hypodermis – merocrine ▪ Secretes pheromones ▪ Ducts are straight ▪ Lined by stratified cuboidal epithelium ▪ Have a narrow lumen
Pacinian corpuscles
-(pressure changes
and vibrations)
-Found in deep der
-mis and hypodermis
